feat: v0.17.0 — ISS-008 toasts for errors/events + browser notifications

lib/useToasts.test.ts

@@ -0,0 +1,27 @@
+import { describe, expect, it } from 'vitest';
+import { MAX_TOASTS, pushToast, type Toast } from './useToasts';
+
+// ISS-008 (v0.17.0): the toast queue's pure core — append + cap at MAX_TOASTS dropping the
+// oldest. The hook itself is a thin useState wrapper around this (auto-dismiss timers are
+// plain setTimeout, covered by e2e via the visible toasts).
+
+const toast = (id: number, message: string): Toast => ({ id, kind: 'info', message });
+
+describe('pushToast', () => {
+  it('appends to an empty queue and preserves order', () => {
+    expect(pushToast([], toast(1, 'a'))).toEqual([toast(1, 'a')]);
+    expect(pushToast([toast(1, 'a')], toast(2, 'b'))).toEqual([toast(1, 'a'), toast(2, 'b')]);
+  });
+
+  it('keeps the newest MAX_TOASTS entries, dropping the oldest beyond the cap', () => {
+    let queue: Toast[] = [];
+    for (let id = 1; id <= MAX_TOASTS + 2; id++) queue = pushToast(queue, toast(id, `m${id}`));
+    expect(queue).toEqual([toast(MAX_TOASTS - 1, 'm3'), toast(MAX_TOASTS, 'm4'), toast(MAX_TOASTS + 1, 'm5'), toast(MAX_TOASTS + 2, 'm6')]);
+  });
+
+  it('does not mutate the input queue', () => {
+    const before = [toast(1, 'a')];
+    pushToast(before, toast(2, 'b'));
+    expect(before).toEqual([toast(1, 'a')]);
+  });
+});